Have a leak on a 62 389 from the rear main seal. The original seal is a rope design, is there any updated options available? The seal isn't that old but still a problem with leaking.

Yes. BOP Engineering has a Viton two-piece rear main seal. It is definitely not a rope seal. Chances are that you will want the 3" version instead of the 3.25" one.

https://www.bopengineering.com/A_Pontiac_Engine_Gaskets_Seals_1.shtml

 

23 minutes ago, Frosty said:

Yes. BOP Engineering has a Viton two-piece rear main seal. It is definitely not a rope seal. Chances are that you will want the 3" version instead of the 3.25" one.

https://www.bopengineering.com/A_Pontiac_Engine_Gaskets_Seals_1.shtml

 

Thank you very much. I see they have a one piece, two piece and an updated rope style seal for the 389. Is there a recommendation? Which one is the best to use?

I've heard that installing the one piece is a two-man job but it seals really well. Someone has to hold up the 80 lb crankshaft while the other person is getting the seal on over the crank and aligning it as it goes into the block.

I have the two piece seal in my 455. It doesn't leak and one person can install it.

If you are looking for something closer to OEM/OER, the rope seal is fine and it's better than a stock rope seal but remember that it is still a rope seal and it may leak over time.

Edited May 7, 20242 yr by Frosty

At the very least after removing the oil pan...You have to remove the rear Main bearing cap in order to access the rear main oil seal...The 2 piece oil seal can be replaced with the engine/transmission still in the car...But you have to be able to lift the engine  enough to be able get the oil pan to clear the crossmember so it will come completely off...To have enough clearance in order to remove the rear Main Bearing cap...Once the cap is out of the way...Then you should be able push/pull the top half of the seal out from over the top of the crankshaft...Then simply slide the new seal into place over the top of the Crank and replace the bottom half in the bearing cap...Pay special attention because the top and bottom half of the seal is different...Use the proper RTV on the surfaces of the ends of the seal where they meet...Don't go crazy with the RTV or it will cause more of a problem than it will solve...Then put everything back together in the reverse order of the way it came apart...Be Sure to use a torque wrench when reinstalling the main bearing cap...I'm not 100%  sure without looking it up....What the main bearing cap torque spec is I think it's somewhere around 40 to 50 ft.lbs... Double that check that...

The one piece seal is realistically something that should pobably be done When the engine is completely torn down during a rebuild....Hope this helps...

TLBT...

I also installed a Viton 2 piece rear main seal on my 389 rebuild. I was advised AGAINST using the one piece. My seal works perfectly. Less than half the cost and easy to install BUT I have to say I would hate to install one whilst the engine was in the car. To get it fitted right, I'd opt to pull the engine. Just my thoughts. The last thing you want is to go to all that trouble and have the damn thing leak.